Mercury switch actuating means



1941- c. w. WADE ETAL 2,251,385

MERCURY SWITCH ACTUATING MEANS Filed Aug. 14, 1940 2 Sheets-Sheet 2 illI lllllll-llllll 3 CHARLES W W a qTTO/PNE v5.

Patented Aug. 5, 1941 MERCURY SWITCH ACTUATING MEANS Charles W. Wade andCharles A. Denny,

Detroit, Mich.

Application August 14, 1940, Serial No. 352,498

7 Claims.

This invention relates to means for rocking a mercury tube switch andparticularly to such means as will actuate the switch where the circuitis to be closed or broken for a very short interval of time.

An important advantage of the invention is that by a very simplemechanism the switch may be actuated in a closely timed cycle as may bedetermined by a revolving member in such manner that the switch will notbe actuated upon reverse travel of that revolving member. A furtherimportant advantage of the invention is that such means are embodied ina novel manner permitting very low cost of production and yet at thesame time permitting accurate operation over a long period of time.

These and many other objects and advantages of the invention will becomeapparent to those versed in the art in the following description of oneparticular form of the invention as illustrated in the accompanyingdrawings, inv which- Fig. 1 is a, top plan View of a structure embodyingthe invention;

Fig. 2, a vertical section on the line 2--2 in Fig. 1;

Fig. 3, a detail illustrating the actuating finger in the normalposition;

Fig. 4, a like detailshowing the finger shifted back of the switchactuatedposition;

Fig. 5, a similar detail showing the finger in its position immediatelyfollowing actuation of the switch;

Fig. 6, a view in side elevation;

Fig. 7, a view in opposite side elevation; and

Fig. 8, a view in rear elevation.

Like characters of reference indicatelike parts throughout the severalviews in the drawings;

Upon any suitable base, such as the plate H3, is mounted an upright postI I. This post I I carries a transverse shaft I2 to which is adjustablyfixed, by means of a set screw I3, a mercury tube switch holder I 4comprising in the usual manner a pair of spaced apart clips betweenwhich the switch I5 is compressively engaged. Also fixed to this shaftI2, herein shown as on the other side of the post Ii, is a switchposition biasing weight It normally dropping by its lower end againstthe end of the adjusting screw ii that is carried by a bracket l8extending from the post i i near its base. The weight I6 is adjustablyposi tioned on the shaft I2 and there secured by means of a set screwI9.

The purpose of the weight It is to rock the switch I5 to either the onor the off positions as may be desired, the switch herein being shownarm 20 by any suitable means, such as the screw 2|, so that the arm 20may swing horizontally. A torsion spring 22 surrounds the pivot screw 2Ito have one end 23 bear against the back side of the arm 20 and theother end 24 bear against the front side of a stop 25 against which thearm 20 is urged and normally positioned by means of the spring 22'.

A spring arm 26, herein shown as a leaf spring, is fixed to the arm 20to extend from its rear side over and under the rocker 2'! that is fixedto the shaft I2. The arm 20 carries a hinged extension 28 that isnormally maintained in an extended position by means of a tension spring29 inter engaging the spring arm 26 and the extension arm 28, theextension arm 28 being secured to the arm 2%) by the pivot pin 30,Fig. 1. The inner end of the extension arm 28 is brought into abutmentwith the arm 20 by the spring 29 to limit backward travel of theextension arm 28 toward the spring arm 26, but permitting reverse travelas indicated by the dash lines in Fig. 1.

The rocker 2"! has an under surface against which the spring arm 25yieldingly bears. As best indicated in Figs. 3-5, this under surfacepermits the spring arm 26 to bear normally against a rear portion, as inFig. 3. This under surface of the rocker 21 is stepped to form ashoulder 3| against which the spring arm 26 may be shifted to rock therocker 21 to a position as indicated in Fig. 4 where the straight camportion 32 of the rocker Zl will push the spring arm 26 downwardlybeyond the step or shoulder 3i to allow the rocker 21 to returnrearwardly while the spring arm 26 moves on relatively to the positionshown in Fig. 5, the combined mass of the switch tube I5 and theweighti6 causing the return movement of the rocker 21. Then the switch arm 26may be moved rearwardly again to the position shown in Fig. 3 1

5;; arm 26 to some such position as indicated in Fig.

3. In the present form, this driving means comprises a shaft 33 on theupper end of which is mounted a disc 34 that carries at least oneupright pin 35. The pin 35 is located at the proper radial distance fromthe center of the disc 34 to be in the path of the outer end of the arm23 so that, upon clockwise travel, Fig. 1, the pin 35 will strike thatarm to push it back and consequently push the spring arm 26 backaccordingly. In the present form of the invention, instead of strikingthe extension arm 28 directly, a roller 35 is mounted on the outer endof the extension arm 28 to be in the path of the pin 35 whereby the pinwill strike that roller 35 to push the extension arm 28' back out of theway with a minimum amount of friction. It is understood, of course, thatwhen the arm 28 is moved backwardly by the pin 35,

the arm is moved accordingly to in turn move the spring arm likewise.The purpose of hinging the extension arm 28 to the arm 23 is topreventdamage to the various parts should the disc 34 and its pin bemoved in a counterclockwise direction. In that event, the extension arm28 would be shifted to the dash line position without setting up anytravel of the spring arm 26 or the arm 29. which is in abutment with thestop 25.

The number of operations per revolution of the disc 34 may, of course,be varied in accordance. with the number of pins 35- carried by the disc34. As indicated, holes 31 are provided in the. disc, 34 to receiveadditional pins 35- as may be desired.

The structure above described will cause an operation of the switch I5once each revolution of the disc- 34, this operation consisting of aclosure of theswitch following shifting of the spring arm 23 rearwardlyof the step 3| on the rocker 21 and the return of that spring arm 25 toits normal position, Fig. 5, which causes the switch [5 to be-rocked toits close-d position and then dropped to its openposition as the springarm 25. leaves the position shown in Fig. 4. As above indicated, theshape of the under surface of the rocker 2'! is such that the arm 26 ispositively pushed downwardly for disengagement with the step 3! ratherthan relying upon a greater travel of the arm 26 which would be requiredin the absence of this construction. The terminal wires 38, 39: of theswitch I5 are carried to any suitable .location, such as the terminalblock 40 which is herein shown as being mounted on the upper end of thepost I I-. Of course by reversely mounting the switch l5, theswitch maybe normally in the closed position and then actuated to an open circuitposition by the structure-above defined.

While we have herein shown and described our invention in the oneparticular form, it is obvious that structural variations may beemployed Without departing from the spirit of the invention and we,therefore, do not desire to be limited to that precise form beyond thelimitations as may be imposed by the following claims.

We claim:

1. In a mercury tube switch actuating mechanism. a switch holder, a rockshaft on which the holder is mounted, means for biasing the holder tooneend of the rocking limit thereof, a rocker attached to said shaft andhaving an outer surface interrupted by a shoulder, a rocker arm springyieldingly pressing against said surface, and means for reciprocatingsaid arm spring through an arc of travel to carry the arm springinitially across and back of said shoulder and allowing the arm springto return against the shoulder thereby to swing said rocker arm andconsequently said switch from its biased position.

2. In a mercury tube switch actuating mechanism, a switch holder, a rockshaft on which the holder is mounted, means for biasing the holder toone end of the rocking limit thereof, a rocker attached to said shaftand having an outer surface interrupted by a shoulder, a rocker armspring yieldingly pressing against said surface, and means forreciprocating said arm spring through an arc of travel to carry the armspring initially across and back of said shoulder and allowing the armspring to return against the shoulder thereby to swing said rocker armand consequently said switch from its biased position, said surfacebeing formed with a camportion to push said arm spring off of saidshoulder for release therefrom upon a predetermined swing of the rockerarm, whereby the switch holder is returned to control of said biasingmeans.

3. In a. mercury tube switch actuating mechanism, a switch holder, arock shaft on which the holder is mounted, means for biasing the holderto one end of the rocking limit thereof, a rocker attached to said shaftand having an outer surface interrupted by a shoulder, a rocker armspring yieldingly pressing against said surface, and means forreciprocating said arm spring through an arc of travel to carry the armspring initially across and back of said shoulder and allowing the armspring to return against the shoulder thereby to swing said rocker armand consequently said switch from its biased position, said surfacebeing formed to push said arm spring off of said shoulder for releasetherefrom upon a pre-determinedswing of the-rocker arm, whereby theswitch holder is returned to control of said biasing means, and springmeans returning said arm spring upon said release to a normal positionahead of said shoulder.

4. In a mercury tube switch actuating mech anism, a rock shaft, a switchactuated through rocking of the shaft, means biasing the shaft to oneend of rocking thereof, a rocker arm carried by the shaft and having anofiset in its peripheral surface, a rocker spring having a pivot to oneside'of said arm and compressibly bearing against said surface, meansfor rocking said spring across said surface in a direction in oppositionto travel thereof induced by said biasing means, and a second biasingmeans normally returning said spring to a position forwardly of offset,whereby said spring rocking means carries the spring. back of saidoffset for engagement therewith and said second spring biasing meansswings said arm by spring abutment with the offset.

5. In a mercury tube switch actuating. mechanism, a rock shaft, a switchactuated through rocking of the shaft, means biasing the shaft to oneend of rocking thereof, a rocker arm carried by the shaft and having anoffset in its peripheral surface, a rocker spring having a pivot to onesideof said arm and compressibly bearing against said surface, means forrocking said spring across said surface in a direction in opposition totravel thereof induced by said biasing means, and biasing means normallyreturning said spring to a position forwardly of ofiset, whereby saidspring rocking means carries the spring back of said offset forengagement therewith and said spring biasing means swings said arm byspring abutment withthe offset, said surface being formed to press saidspring downwardly out of engagement with the offset upon predeterminedswing of the arm to return the spring to a position forwardly of theoffset.

6. In a mercury tube switch actuating mechanism, a rock shaft, a switchactuated through rocking of the shaft, means biasing the shaft to oneend of rocking thereof, a rocker arm carried by the shaft and having anoffset in its peripheral surface, a rocker spring having a pivot to oneside of said arm and compressibly bearing against said surface, meansfor rocking said spring across said surface in a direction in oppositionto travel thereof induced by said biasing means, and biasing meansnormally returning said spring to a position forwardly of offset,whereby said spring rocking means carries the spring back of said offsetfor engagement therewith and said spring by the shaft and having anoffset in its peripheral surface, a rocker spring having a pivot to oneside of said arm and comp-ressibly bearing against said surface, meansfor rocking said spring across said surface in a direction in oppositionto travel thereof induced by said biasing means, and biasing meansnormally returning said spring to a position forwardly of offset,whereby said spring rocking means carries the spring back of said offsetfor engagement therewith and said spring biasing means swings said armby spring abutment with the offset, a reciprocating arm carrying saidspring, an extension from. said last arm, a rotatable shaft, a crank pincarried off center of and rotatable with the shaft in the path of saidextension, whereby rotation of the shaft will actuate said spring, saidextension being hinged to said reciprocating arm to be rigid in effecttherewith in one direction, and a spring retaining the extension in saidrigid position allowing the extension to swing from its arm in the otherdirection to permit said crank pin to pass the extension in that otherdirection without shifting said reciprocating arm.

CHARLES WM. WADE. CHARLES A. DENNY.

